Wiper arms of the described above type are well known in the prior art and German (DE) patent applications No. 23 26 183 and No. 25 11 013 are examples of such structure. The main disadvantage of the wiper arms disclosed in said two patent applications, i.e. of the conventional wiper arms, is their relatively high production cost, cost which is mainly due: (a) to the fact that they necessitate the assembly of numerous parts; (b) to the complexity of certain parts; and (c) to the necessary use of relatively expensive materials such as, for example, special alloys for the mounting head.
The complexity of the conventional wiper arms is also due to the fact that the articulation between the mounting head and the channel is accomplished by means of a rivet. This requires the assembly of several supplementary parts, as can be seen in FIG. 2 of the German patent application No. 23 26 183.
Also the caps described in the two above mentioned German patent applications, and generally most conventional caps, are relatively fragile. Thus, the removable cap of the German patent application No. 23 26 183 often breaks at the articulation between the mounting head and the channel.